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For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 STS 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 Power Door Latch System Malfunction

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Door Latch Motor Control

1

1

1

--

Door Unlatch Motor Control

1

1

1

--

Door Lock Actuator Deadbolt Control

2

2

2

--

Door Lock Actuator Lock Control - Right Rear

2

2

2

--

Door Lock Actuator Lock Control - Left Rear

2

2

2

--

Door Lock Actuator Unlock Control - Left Rear

2

2

2

--

Door Lock Actuator Unlock Control - Right Rear

2

2

2

--

Driver Door Lock Actuator Unlock Control

2

2

2

--

Driver Door Lock Switch Lock Signal

B3150 02

2

2

--

Driver Door Lock Switch Unlock Signal

B3140 02

2

2

--

Door Lock Actuator Unlock Control - Front Passenger

2

2

2

--

Left Front Door Handle Switch - Lift Switch Signal

B3849 02

1

1

--

Left Front Door Handle Switch - Unlatch Enable Signal

1

1

1

--

Left Front Door Open Switch Signal

2

2

2

--

Left Rear Door Open Switch Signal

2

2

2

--

Passenger Door Lock Switch Lock Signal

B3150 02

2

2

--

Passenger Door Lock Switch Unlock Signal

B3140 02

2

2

--

Right Front Door Handle Switch - Lift Switch Signal

B3849 02

1

1

--

Right Front Door Handle Switch - Unlatch Enable Signal

1

1

1

--

Right Front Door Open Switch Signal

2

2

2

--

Right Rear Door Open Switch Signal

2

2

2

--

Driver Door Switch Assembly (DDSA) Ground

--

2

--

--

Door Handle Switch Assembly - LF Ground

--

1

--

--

Door Handle Switch Assembly - RF Ground

--

1

--

--

Door Latch Assembly - Driver Ground

--

2

--

--

Door Latch Assembly - Passenger Ground

--

2

--

--

Door Latch Assembly - Left Rear Ground

--

2

--

--

Door Latch Assembly - Right Rear Ground

--

2

--

--

Passenger Door Lock Switch Ground

--

2

--

--

1. Power Door Latch System Malfunction

2. Power Door Locks Inoperative

Circuit/System Description

When either exterior door handle is lifted, switched ground signals are sent to the driver door module (DDM) or front passenger door module (PDM) and the remote control door lock receiver (RCDLR) through the LF or RF door handle switch signal circuits. Upon receipt of these inputs, the DDM or PDM and the RCDLR will check the status of the power door lock system. Control of the power door latches is dependent on the door lock status. If the status of the door lock system is UNLOCK, the power door latches will electrically release after lifting the exterior door handle. If the status of the door lock system is LOCK, one of the following inputs will be required before the latch will release:

    • A door unlock switch activation
    • A door key cylinder unlock switch activation
    • An active keyless entry unlock command
    • A passive keyless entry unlock command message is received by the DDM or PDM from the RCDLR

Once the enable criteria has been met, the DDM or PDM will supply power and ground to the door latch motor control circuits and the door will release.

Reference Information

Schematic Reference

Door Lock/Indicator Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Door Latch Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. Ignition ON, observe the scan tool Driver Door Module Driver Door Handle parameter while using the exterior driver door handle. The parameter should change between Active and Inactive.
    2. ⇒If the value does not change between the commanded states, refer to Door Handle Lift Switch Malfunction.
  2. Observe the scan tool Passenger Door Module Passenger Door Handle parameter while using the exterior passenger door handle. The parameter should change between Active and Inactive.
    3. ⇒If the vaule does not change between the commanded states, refer to Door Handle Lift Switch Malfunction.
  3. Observe the scan tool Remote Control Door Lock Receiver Ext. Driver Door Handle Switch parameter while using the exterior driver door handle. The parameter should change between Active and Inactive.
    4. ⇒If the value does not change between the commanded states, refer to Door Handle Lift Switch Malfunction.
  4. Observe the scan tool Remote Control Door Lock Receiver Ext. Psgr. Door Handle Switch parameter while using the exterior passenger door handle. The parameter should change between Active and Inactive.
    5. ⇒If the value does not change between the commanded states, refer to Door Handle Lift Switch Malfunction.
  5. Command the LF latch solenoid ON and OFF with a scan tool. The LF door latch should LOCK and UNLOCK when changing between commanded states.
    6. ⇒If the LF latch does not LOCK or UNLOCK, refer to Power Door Latch Malfunction.
  6. Command the RF latch solenoid ON and OFF with a scan tool. The RF door latch should should LOCK and UNLOCK when changing between commanded states.
    7. ⇒If the RF latch does not LOCK or UNLOCK, refer to Power Door Latch Malfunction.

Circuit/System Testing

Door Handle Lift Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate exterior door handle switch assembly and the X1 harness connector at the RCDLR.
  2. Test for less than 10.0 ohms between the ground circuit terminal 6 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Door Handle Switch parameter is Inactive.
    4. ⇒If not the specified value, test the signal circuit terminal 5 for a short to ground. If the circuit tests normal, replace the door module.
  4. Install a 3A fused jumper wire between the signal circuit terminal 5 and ground. Verify the scan tool Door Handle Switch parameter is Active.
    5. ⇒If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the door module.
  5. Connect the X1 harness connector at the RCDLR and disconnect the X2 harness connector at the door module.
  6. Verify the scan tool Remote Control Door Lock Receiver Ext. Door Handle Switch parameter is INACTIVE.
    7. ⇒If not the specified value, test the signal circuit terminal 5 for a short to ground. If the circuit tests normal, replace the RCDLR.
  7. Install a 3A fused jumper wire between the signal circuit terminal 5 and ground. Verify the scan tool Remote Control Door Lock Receiver Ext. Door Handle Switch parameter is Active.
    8. ⇒If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the RCDLR.
  8. If all circuits test normal, test or replace the exterior door handle switch assembly.

Door Handle Unlatch Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate exterior door handle switch.
  2. Test for less than 10.0 ohms between the ground circuit terminal 3 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, doors UNLOCKED, verify a test lamp illuminates between the signal circuit terminal 4 and ground.
    4. ⇒If the test lamp does not illuminate, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the door control module.
  4. Disconnect the X1 harness connector at the door module.
  5. Verify a test lamp does not illuminate between the signal circuit terminal 13 and ground.
    6. ⇒If the test lamp illuminates, test the signal circuit for a short to voltage.
  6. If all circuits test normal, test or replace the exterior door handle switch.

Power Door Latch Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate door latch assembly.
  2. Test for less than 10.0 ohms between the control circuit terminal listed below and ground.
    3. • RHD terminal 9
    • LHD terminal 4
    ⇒If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the door control module.
  3. Test for less than 10.0 ohms between the control circuit terminal listed below and ground.
    4. • RHD terminal 8
    • LHD terminal 3
    ⇒If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the door module.
  4. Connect a test lamp between the control circuit terminals listed below.
    5. • RHD terminal 8 and terminal 9
    • LHD terminal 3 and terminal 4
  5. Command the Latch Solenoid ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    6. ⇒If the test lamp is always OFF during either of the commands, test either control circuit for a short to ground. If the circuits test normal, replace the door module.
  6. If all circuits test normal, test or replace the door latch assembly.

Component Testing
  1. Ignition OFF, disconnect the harness connector at the appropriate door latch.
  2. Install a 15A fused jumper wire between one of the control terminals and 12V. Momentarily install a jumper wire between the other control terminal and ground. Reverse the jumper wires at least two times, the door latch should perform the LOCK/UNLOCK functions.
    3. ⇒If it does not perform as specified, replace the door latch

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Front Side Door Outside Handle Replacement
    •  Front Side Door Lock Replacement
    •  Control Module References for DDM, PDM, or RCDLR replacement, setup, and programming